Means for directing engine cooling air



Jan. 24, 1939.

T. B. RHINES MEANS FOR DIRECTING ENGINE COOLING AIR 2 She'ets-Sheet 1 Filed Nov. 5, 1956 INVENTOR. 7720:1255 Rhines- B ATTORNEY Jan. 24, 1939. T. B. RHINES ,1

MEANS FOR DIRECTING ENGNE COOLING AIR Filed Nov. a, 1956 2- Sheets-Sheet 2 IN VEN. TOR. T/YUMESHHHiHBS y/zw "Q 1 ATTORNEY Patented Jan. 24, 1939 I MEANS FOR DIRECTING ENGINE COOLING Thomas B. Rhinos, Hartford, Gonna, assignor to United Aircraft Corporation, East 0onn., a corporation of Delaware Hartford,

Application November 3, 1938, Serial No. 108,941 14 Claims. (61. 123-111) This invention relates to improvements in means for cooling an internal combustion engine and has particular reference to improved means for cooling a radial air-cooled internal combustion engine such as is ordinarily employed for the propulsion of aircraft.

An object of the invention resides in the provision of improved means for augmenting the volume of cooling air flowing past the heat exchanging surfaces of the engine cylinders. A further object resides in the improvement residing in the inclusion in one element of means for increasing the velocity of the engine cooling air as it enters and as it leaves the engine compartment.

An additional object resides in the provision of improved means for guiding the engine cooling air at high velocity along the heat exchanging surfaces of the engine cylinders.

Other objects and advantages will be more particularly pointed out hereinafter or will become apparent as the description proceeds.

In the accompanying drawings in which like reference numerals are used to designate similar parts throughout, there is illustrated a suitable mechanical embodiment of what is now consid-A ered to be the preferred form of the idea of the invention. The drawings, however, are for the purpose of illustration only and are not to be taken as limiting the. invention, the scope of which is to be measured entirely by the scope of the appended claims.

In the accompanying drawings, Figure 1 is a partly schematic elevational view ofa radial internal combustion engine and a propeller driven thereby, the engine enclosing cowl and an improved engine cooling air directing means con- .structed according to the idea of this invention being shown in sections to better'illustrate the While the device of the invention has been found to be particularly adaptable to a radial air-cooled engine of the character indicated, it is to be understood that the invention is in no way limited to any particular type of engine but may be applied to any installation in which it would be effective to improve the cooling characteristics of the engine.-

The engine illustrated is provided at its rear end with a group of accessories generally indicated at It including such elements as the carburetor, the magneto, the generator and other devices necessary or convenient to the operation of the engine or the airplane. It is within the scope of the invention, however, to apply the"improved cooling means to an engine having some or all of the accessories at its front end adjacent to the nose piece is from which projects a propeller shaft 20 upon which is mounted a suitable propeller generally indicated at 22.

The engine is mounted upon a fuselage, wing, or nacelle structure by suitable mounting means generally indicated at 24 and may be provided with a separate oil tank 26 and an oil cooler 28 which may be disposed in a channel 30 provided in the streamlined cowling 32 surrounding the engine.

The engine is preferably provided with pressure bafiles 34 disposed between adjacent cylinders and extending from the crankcase H to the adjacent inner surface of the cowl 32. A suitable form of pressure bailles is illustrated and described in Patent No. 2,031,541 issued to A. L. MacClain February 18, 1936.

The front end of the engine surrounding cowl 32 is provided with an annular opening surrounded by loop or beaded-over edge 38 which is preferably mounted upon the outer end of the cylinder I! by suitable means such as is indicated device illustrated, a substantially cylindrical member 44 is provided witha transverse end wall 46 having a central aperture 48 surrounding the shaft 20 and through which a portion of the hub Y of the propeller 22 may project. This. end wall is provided adjacent its outer circumference with a series of apertures within which are disposed mounting bushings 50 preferably formed of rubber or some similar resilient material. The propeller hub is held together by suitable clamp bolts 52 and these bolts are provided with extensions which extend through the mounting bushings 50 to secure the member 44 to the propeller, the bolts being provided upon one side of the bushings with suitable abutinents as indicated at 54 and upon the other side thereof with screw threaded nut as indicated at 56.

A plurality of radially disposed fan blades 58 are secured at their inner ends to the outer surface of the rearward portion of the member 44 and are secured at their outer ends to the inner circumference of an annular member having a partly toroid shape. The radial vanes 58 extend for only a portion of the distance from the member 44 to the inner portion of the edge 38 of the cowl 32 and the annular member 60 partly surrounds the rounded edge 33 of the cowl and is spaced therefrom. Within the member 80 there is disposed an inner annular member 62 having a shape similar to shape of the member 60 but having smaller dimensions. A plurality of radially extending vanes 64 are disposed between the outer annular member "60 and the inner annular member 82.

In the form of the'invention shown, the annular-member 60 is so dimensioned that its inner circumference, to which the outer end of the radialfan blades 58 are attached, substantially coincides with the circumference including the medial lines defining the division between the barrel and the head portions of the cylinders l2. An annular guide member 66 having a radius substantially the same as the radius of theinner circumference of annular member 60 is disposed about the engine ill in such a manner that it forms in effect a continuation of the inner portion of the annular member 66 across the engine. This guide member extends from a position somewhat in front of the engine to a position beyond the rear of the engine'cylinders and preferably extends a somewhat greater distance to the rear upon that side of the engine upon which the engine carburetor is located. 'In the form of the invention illustrated, the guide member 86 is provided with an aperture 68 opening into a v duct 10 leading to the carburetor".

The fan blades 58 are twisted or disposed at an angle to the direction of rotation .of the blower 42 so that they will direct a stream of air axially into the engine within the annular guide member 86. If desired, these fan blades may be formed with an airfoil section.

From this part of the description, it will be observed that the fan constituted by the cylindrical member 44, the annular member 60 and the series of interconnecting fan blades 58, constitutes an axial fan for forcing air from the space surrounding the hub of the propeller 22 into the engine compartment.

The vanes 64 are curved in the plane including the axis of the engine ill and blower 42 and may also be curved in a direction circumferential of the blower 42 to provide a spiral effect. The fan element comprising the outer annular member 60, the inner annular member 62 and the vanes 64 has an air inlet opening 14 disposed within the front end of the cowl 32 and an air exit or vent opening 16 disposed outside of the cowl 32 and radially spaced from the inlet opening I4.

From this description, it will be observed that the fan comprising the outer annular member 60, the inner annular member 62' and the vanes 64 is a centrifugal fan for moving air from the interior of the cowl 32 to the outside thereof.

In the form of the invention illustrated the annular air vent opening 16 is disposed adjacent to the forward end of the cowl .32 where it will be in the low air pressure region existing over the cowl nose. The low pressure existing in this area will materially assist in removing the air from the interior of the engine compartment. The ventopening 16 is alsor'earwardly directedand has a diameter such that the opening is disposed directly to the rear of relatively eflicient portions of the blades of the propeller 22 so that the air stream created'by the propeller, in fio wing past the vent opening will also assist in withdrawing the air from the interior of the engine compartment. Obviously, the air inlet opening may be located-in a spinner disposed on the front or propeller side of the fan without in any way exceeding the scope of the invention.

From the above description, it will be observed that engine cooling air will be directed in a substantial axial direction by the fan bladefiflf from the space surrounding the hub of pro'pellerQ ZfZ into the annular guide member 66 and past the barrel portions of the cylinders l2. A portion of the air will be diverted from the interior of the guide member 66 into the carburetor "through the duct 10 and the remainder will flow outof the annular guide member 6'5 into the space surrounding the engine accessories is. As the cylinder barrels are not excessively hot, the temperature of the air leaving the guide member 66 will be sufiiciently low to adequately cool the engine accessories. If the accessories are mounted at the front of the engine, they will be cooled by the cooling air entering the engine compartment; From the space at the rear of the engine surrounding the accessories Hi, the air is drawn into the annular space between the guide member 66 and the interior of the cowl 32. As the air is drawn through this space, it flows past and cools the head portion of the cylinders l2. From trifugal fan including the vanes 64 and isvented rearwardly over' the exterior of the cowl 32.

Thus,-it will be observed that there has been provided an extremely simple and eifective 'arfrangement for materially augmenting the flow of engine cooling air past the heat exchanging surfaces of the engine.

While there has been illustrated and described a suitable mechanical embodiment of what is now considered to be the preferred form of the idea of the invention, it is to be understood that the invention is not limited to the particular construction so illustrated and described but that such changes in the size, shape and arrangement of parts may be res rted to as come within the scope of the subjoincd claims.

Having now described the invention so that others skilled in the art may clearly understand the same, what is claimed and what it is desired to secure by Letters Patent is as follows:

1. In combination with an air-cooled engine and a cowl enclosure therefor, means driven by said engine for forcing air into and out of said enclosure, said means comprising, an inner axial fan for forcing air into said enclosure, and an outer centrifugal fan for forcing air out of said enclosure.

2. In combination with an air-cooled engine and a cowl enclosure therefor, means driven by said engine for forcing air into and out of said enclosure, said means comprising, an inner axial fan for forcing air into said enclosure, and an outer centrifugal fan for forcing air out of said enclosure, and an annular guide member extend- (iii ing across said engine and positioned substantially. on the circumference dividing said two fans for separating the stream of air entering said enclosure from the stream of air leaving said enclosure.

3. In combination with an air-cooled engine having a plurality of cylinders each comprising a and a separate rotatable portion for forcing cooling air in the opposite direction over the head portions of said cylinders.

4. In combination with an air-cooled engine having a plurality of cylinders each comprising a barrel portion and a head portion, and an openended enclosure for said engine, means positioned adjacent the open end of said enclosure and driven by said engine having an axially acting portion for forcing cooling air in one direction over the barrel portions of said cylinders, and a centrifugally acting portion for drawing the same air in the opposite direction over the head portions of said cylinders.

5. In combination with an air-cooled engine having a plurality of cylinderseach comprising a barrel portion and a head portion, and an openended cowl enclosure for said engine, means positioned adjacent the open end of said enclosure and driven by said engine having an inner portion for forcing engine cooling air intosaid enclosure and across the barrel portions of said cylinders and an outer portion for drawing the same air across the head portions of said cylinders and out of said enclosure.

6. In combination with an air-cooled engine having a plurality of cylinders each comprising a barrel portion and a head portion, and an open-ended cowl enclosure for said engine, means positioned'adjacent the open end of said enclosure and driven by said engine for forcing engine cooling air into said enclosure and across the barrel portions of said cylinders and forcing the same air across the head portions of said cylinders and out of said enclosure, and an annular guide member separating the space including the barrel portions of said cylinders from the space including the cylinder head portions.

7. In combination with an air-cooled engine having a plurality of cylinders each comprising a barrel portion and a head portion, a group of engine accessories at the rear of said engine, and an open-ended cowl enclosure for said engine, means positioned adjacent the open end of said enclosure and driven by said engine for'forcing engine cooling air into said enclosure and across the barrel portions of said cylinders and forcing the same air across the head portions of said i closure, bothlof said means being arranged to cylinders and out of said enclosure, and an annular guide member separating the space including said cylinder barrel portionsfrom the space including said head portions, said annular guide member terminating short of the space including said engine accessories. H

8. In combination with an air-cooled engine having a plurality of cylinders each comprising a barrel portion and a head portion, a carburetor for supplying a combustible mixture to said engine, and an open-ended cowl enclosure for said engine, means positioned adjacent to the open end of said enclosure and driven by said engine for forcing engine cooling air into said enclosure and across the barrel portions of said cylinders and forcing the same air across the head portions of said cylinders and out of said enclosure, an annular guide member extending across said engine and separating the space including said cylinder barrel portions from the space including said cylinder head portions, and means for conducting air from the interior of said annular guide member to said carburetor.

9. In combination with an air-cooled engine and an open-ended cowl enclosure therefor, means positioned adjacent to the open end of said cowl and driven by said engine for forcing 'air into and out of said enclosure, said means comprising, a two part fan driven by said engine and an outer centrifugal fan portion surrounding said inner fan portion for forcing the same air out of said enclosure, said centrifugal fan portion 'havinglan annular air entrance opening within the enclosure, and an annular air vent opening located outside of said enclosure and-in a region of low air pressure over the nose of said cowl enclosure.

11. In combination with an air-cooled engine and an open-ended cowl enclosure therefor, means driven by said engine and positioned adjacent to the open end of said enclosure for forcing air into and out of said enclosure, said means comprising, a two part fan having an inner axial fan portion for directing engine cooling air into said enclosure, and an outer centrifugal fan portion surrounding said inner axial fan portion for forcing the same air out of said enclosure, said centrifugal fan portion having an annular air entrance opening within the enclosure, and a rearwardly directed air vent opening outside of said enclosure, said annular air vent opening having a diameter suflicient to bring the opening opposite portions of the propeller blades having a relatively high aerodynamic efficiency.

12. In a vehicle engine cooling means including a streamlined open-ended engine enclosure and an engine driven blower adjacent tothe open end of the enclosure, means constituting a portion of said blower for increasing the flow of air into said enclosure through said open end, and other ineans also constituting a portion of said blower for drawing air out of the same end of said encharge said cooling air in the same direction as the direction of air flow past said enclosure when said vehicle is moving.

13. In an engine cooling means including a group of heat radiating surfaces and an openended enclosure therefor, power actuated'means disposed adjacent the open end of said enclosure for forcing air into and out of the enclosure,

said means comprising, an inner axial fan for forcing air into said enclosure, and an outer centrifugal fan for forcing the same air out of said enclosure.

closure, said means comprising, an inner axial fan. for forcing air into said enclosure, and an closure.

outer centrifugal fan for forcing air out of said enclosure, and means within said enclosure for separating the stream of air entering the enclosure from the stream of air leaving the en- 'I'HbMAs B. RHINES. 

